In essence, material possessions or wealth (9)
I believe the answer is:
substance
I believe this clue is a quadruple definition!!
'in essence' is the first definition.
'substance' can be an answer for 'essence' (synonyms). I am not sure about the 'in' bit.
'material' is the second definition.
(I've seen this before)
'possessions' is the third definition.
(thesaurus)
'or' acts as a link.
'wealth' is the fourth definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for substance that I've seen before include "Matter or material that a thing is made of" , "Property" , "Physical matter" , "Basic matter" , "wealth" .)